土壤酸胁迫对黑麦草生长生理及镉富集特征的影响
戴学斌1, 许瑜兴1, 邓 义1, 马佳珠1, 陈莉莉1, 穆兴民2

(1.玉溪师范学院 地理与国土工程学院, 云南 玉溪 653100; 2.中国科学院 水利部 水土保持研究所, 陕西 杨凌 712100)

多年生黑麦草; 镉富集; 酸胁迫; 植物修复

Effects of Soil Acid Stress on Growth Physiology and Cadmium Enrichment Characteristics of Lolium perenne
DAI Xuebin1, XU Yuxing1, DENG Yi1, MA Jiazhu1, CHEN Lili1, MU Xingmin2

(1.College of Geography and Land Engineering, Yuxi Normal University, Yuxi, Yunnan 653100, China; 2.Institute of Soil and Water Conservation, CAS & MWR, Yangling, Shaanxi 712100, China)

Lolium perenne; Cd enrichment; acid stress; phytoremediation

备注

为探讨黑麦草对酸胁迫的耐性和对Cd污染土壤修复的可行性,通过盆栽试验,研究了不同浓度土壤酸胁迫对黑麦草种子萌发、植物生长生理特征的影响及黑麦草对Cd的富集特征。结果显示:较高浓度的土壤酸胁迫(pH值4.0)对黑麦草的种子萌发、植物生长生理及Cd富集能力具有明显抑制作用。当土壤pH值为4.0时,黑麦草种子发芽势、发芽率、植物株高、根长、地上生物量、地下生物量、总生物量、叶绿素总量和根系活力都最低,叶片和根系丙二醛含量最高,根细胞超微结构受损严重,植物地上部与根部的Cd含量和富集系数最低。较低浓度的土壤酸胁迫(pH值4.5～6.0)对黑麦草种子发芽势和发芽率具有一定的促进作用。黑麦草的根长、地下生物量和根冠比在较低浓度土壤酸胁迫(pH值4.5～6.0)下无显著差异,且植物生长良好。随着土壤pH值升高,黑麦草的叶绿素总量和根系活力显著增加,叶片和根系的丙二醛含量显著降低。当土壤pH值为6.0时,黑麦草根细胞壁、细胞膜、细胞基质和线粒体结构较完整清晰。黑麦草地上部与根部的Cd含量和富集系数在不同浓度土壤酸胁迫下差异显著,土壤pH值在适度弱酸性(pH值4.5和pH值5.0)条件下更有利于黑麦草对Cd的富集。黑麦草根部对Cd的富集能力大于地上部。研究表明,黑麦草对土壤酸胁迫的耐性较强,在酸性土壤条件下的土壤Cd污染植物修复中具有较大利用潜力。
This study was to explore the tolerance of Lolium perenne to acid stress and the feasibility of remediation of Cd contaminated soil. A pot experiment was conducted to study the effects of different soil acid stresses on seed germination, plant growth physiological characteristics and Cd enrichment characteristics of Lolium perenn. The results showed that higher level of soil acid stress(pH 4.0)significantly inhibited the seed germination, plant growth physiology and Cd enrichment capacity of Lolium perenn; when the soil pH value was 4.0, seed germination potential, germination rate, plant height, root length, aboveground biomass, underground biomass, total biomass, total chlorophyll and root vigor were the lowest, MDA contents in leaves and roots were the highest, the ultrastructure of root cells was seriously damaged, and the Cd content and enrichment coefficient of shoot and root were the lowest; lower level of soil acid stress(pH 4.5～6.0)could promote the germination potential and germination rate of Lolium perenn; there was no significant difference in root length, underground biomass and root-shoot ratio under low soil acid stress(pH 4.5～6.0), and the plants grew well; with the increase of soil pH value, the total chlorophyll content and root vigor of Lolium perenn increased significantly, and the MDA contents of leaves and roots decreased significantly; when the soil pH value was 6.0, the structure of cell wall, cell membrane, cell matrix and mitochondria of root was complete and clear; Cd content and enrichment coefficient of Lolium perenn differed significantly under different soil acid stresses, and soil pH value was more favorable for Cd enrichment under the condition of moderate weak acidity(pH 4.5 and pH 5.0). The Cd accumulation ability of root was higher than that of shoot. These results showed that Lolium perenn had strong tolerance to soil acid stress, and had great potential in phytoremediation of Cd contaminated soil under acidic soil conditions.